This follows a highly critical alert from Secunia. I like Firefox, so I’ll probably reinstall it asap. Meanwhile I have made Google Chrome my default browser. It gets 100% thumbs up from Secunia. IE8 doesn’t, but the risk there is rated moderate, but I don’t use IE8 often.
Update 16 July
I have reinstalled Firefox, despite the warning, hoping my various cyber condoms make the problem less significant. I am nonetheless keeping Chrome as my default browser for the time being. It is less resource hungry than it was when I first tried it and it certainly looks good.